Apparatus for brazing radial bearings and related methods

ABSTRACT

Apparatuses and methods are provided for manufacturing bearing assemblies. In accordance with one embodiment, a fixture is provided for use in brazing bearing elements to a bearing ring. The fixture comprises a substantially annular body and at least one or more force-applying mechanism associated with the annular body. The force applying mechanisms include a push rod disposed within a channel that is formed in the annular body, the push rod being displaceable within the channel. A biasing member is configured to bias the push rod in a radial direction relative to the annular body. In one embodiment, a plurality of force-applying mechanisms are circumferentially spaced about the substantially annular body. In one embodiment, the push rods extend radially inwardly from a peripheral surface of the body, while in another embodiment the push rods extend radially outwardly from peripheral surface of the body.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present invention is a continuation application of, and claimspriority to U.S. patent application Ser. No. 14/942,541, filed on Nov.16, 2015, which is a continuation of and claims priority to U.S. patentapplication Ser. No. 14/592,644, filed on Jan. 8, 2015, issued as U.S.Pat. No. 9,188,158 on Nov. 17, 2015, which claims priority to, U.S.patent application Ser. No. 13/827,529, filed on Mar. 14, 2013, issuedas U.S. Pat. No. 8,950,649 on Feb. 10, 2015, entitled APPARATUS FORBRAZING RADIAL BEARINGS AND RELATED METHODS, the disclosures of each ofwhich are incorporated by reference herein in their entireties.

TECHNICAL FIELD

The present invention relates to radial bearings, and more particularlyto radial bearing apparatuses and methods for the manufacture of radialbearings.

BACKGROUND

Conventional bearing apparatuses include bearing surfaces that moverelative to one another are known in the art. For example, radialbearings and so-called “thrust bearings” may conventionally includebearing surfaces that may at least partially contact and move or sliderelative to one another or otherwise develop a fluid film between forhydrodynamic operation. Such bearing surfaces may include a superhardmaterial for resisting wear during use of the bearing apparatus. In oneexample, bearing surfaces in a bearing apparatus may comprise a hardmaterial such as diamond (e.g., polycrystalline diamond).

One application for bearing apparatuses, such as radial bearings andthrust bearings, is in association with drilling equipment utilized insubterranean drilling. Particularly, drilling motors have been utilizedfor drilling boreholes into subterranean formations, especially for oilor gas exploration. In a typical downhole drilling motor, the motor issuspended at the lower end of a string of drill pipe comprising a seriesof pipe sections connected together at joints and supported from thesurface. A rotary drill bit (e.g., a fixed cutter drill bit, roller conedrill bit, a reamer, etc.) may be supported below the drilling motor(via pipe sections, drill collars, or other structural members as knownin the art) or may be directly connected to the downhole motor, ifdesired. Drilling fluid is commonly circulated through the pipe stringand the motor to generate torque within the motor, causing the rotarydrill bit to rotate. The drilling fluid may then be returned to thesurface through the annular space between the drilled borehole and thedrill string and may carry the cuttings of the subterranean formation tothe surface.

Downhole drilling motors may include bearing apparatuses, such as thrustbearings or radial bearings. In one embodiment, bearing assembliescomprised of a plurality of hard bearing elements, such as diamondbearing elements, may be coupled to the rotating bearing ring and thenon-rotating bearing ring. The bearing elements are positioned adjacentone another so that the diamond bearing surfaces of the non-rotatingbearing ring and rotating bearing ring may contact one another duringcertain operating conditions or may operate hydrodynamically under otheroperating conditions.

Bearing elements have traditionally been secured to bearing apparatusesthrough using various methods, including brazing the bearing elements toa rotating bearing ring and a non-rotating bearing ring of a bearingapparatus. However, conventional brazing techniques typically requireexposing the parts to be brazed to high temperatures for extendedperiods of time to melt a brazing filler metal used to braze the parts.Bearing parts, such as rotating bearing rings and non-rotating bearingrings, are often placed in a heating oven for a few hours in order toheat the parts and the brazing filler metal to the appropriate brazingtemperature.

During the manufacture of bearing assemblies, it can be difficultmaintaining individual bearing elements in a desired position andorientation, relative to a bearing ring, while the bearing elements areaffixed to the bearing ring. For example, the bearing elements may bebrazed to the bearing ring, requiring the bearing assembly to besubjected to elevated temperatures. During such a high temperatureprocess, the bearing elements may move or change their positionsrelative to the bearing ring, causing the bearing element to be out ofan acceptable tolerance range and resulting in a bearing surface thatdoes not match the geometric design of the bearing assembly.

It is a desire within the industry to continually improve bearingassemblies, bearing components, and the processes associated withmanufacturing such components and assemblies.

BRIEF SUMMARY OF THE INVENTION

In accordance with the present invention, apparatuses and methods areprovided for manufacturing bearing assemblies. In accordance with oneembodiment, a fixture is provided for use in brazing bearing elements toa bearing ring. The fixture comprises a substantially annular body andat least one force-applying mechanism associated with the annular body.The at least one force applying mechanism includes a push rod disposedwithin a channel formed in the annular body and is displaceable withinthe channel. The push rod is configured to apply a force to an externalcomponent in a radial direction relative to the annular body. In oneembodiment, a biasing member is configured to bias the push rod in theradial direction relative to the annular body. The at least oneforce-applying mechanism may include a plurality of force applyingmechanisms circumferentially spaced about the substantially annularbody.

In one embodiment, the push rod of the force-applying mechanism isselectively positionable in an extended state and a retracted state. Theforce applying mechanism may further include a handle coupled with thepush rod which may be used in selectively positioning the push rod. Inone embodiment, the substantially annular body includes an opening thatis in communication with channel, wherein the handle extends through theopening. Such an opening may be configured as substantially L-shapedhaving a first leg and a second leg. The handle may be selectivelypositionable within the first leg and the second leg such that the pushrod is in a retracted state when the handle is positioned within thesecond leg.

In one embodiment, the biasing member includes a coiled spring disposedwithin the channel. An abutment member may be coupled with the body andconfigured to provide an abutment surface for the coiled spring. Forexample, the abutment member may include a pin extending at leastpartially across the channel.

In one particular embodiment, the push rod extends from a radially innerperipheral surface of the annular body when in the deployed state. Inanother embodiment, the push rod extends from a radially outerperipheral surface of the annular body when in the deployed state.

In accordance with another aspect of the invention, a method of brazinga plurality of bearing elements to a bearing ring is provided. Themethod comprises providing a bearing assembly, the bearing assemblyincluding a bearing ring and a plurality of bearing elements each beingpositioned within an associated pocket, of a plurality of pockets,formed in the bearing ring. The bearing assembly is positioned adjacenta fixture, the fixture comprising a substantially annular bearing ringand a plurality of circumferentially spaced force-applying mechanisms. Aforce is applied to each of the plurality of bearing elements with apush rod of an associated force-applying mechanism and the bearingelements are brazed to the bearing ring while the applied force to eachof the bearing elements is maintained by the associated push rod.

In one embodiment, application of a force to each of the plurality ofbearing elements with a push rod includes selectively positioning eachpush rod from a retracted state to a deployed state relative to thefixture body.

The method may further comprise removing the bearing assembly from thefixture subsequent the brazing, wherein removing the bearing assemblyincludes selectively positioning at least some of the push rods of theforce applying mechanisms from a deployed state to a retracted state.

In one embodiment, selectively positioning at least some of the pushrods of the force applying mechanisms from a deployed state to aretracted state may further include maintaining the at least some pushrods in the retracted state against a biasing force without operatorassistance.

Features, aspects and acts of any of the various embodiments describedherein may be combined, without limitation, with other describedembodiments.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The foregoing and other advantages of the invention will become apparentupon reading the following detailed description and upon reference tothe drawings in which:

FIG. 1 is a top view of an apparatus according to at least oneembodiment of the present invention in a first state;

FIG. 2 is a top view of the apparatus shown in FIG. 1 while in a secondstate;

FIG. 3 is a cross-sectional side view of a portion of the apparatusshown in FIG. 1;

FIG. 4 is a top view of an apparatus engaged with a radial bearingaccording to an embodiment of the present invention;

FIG. 5 is an enlarged detail view of a portion of the apparatus andbearing shown in FIG. 4;

FIG. 6 is a partial cross-sectional view has taken along line “6-6” inFIG. 5;

FIG. 7 is a partial cross-sectional view has taken along line “7-7” inFIG. 6;

FIG. 8 is a top view of an apparatus according to another embodiment ofthe present invention;

FIG. 9 is a top view of an apparatus engaged with a radial bearingaccording to at least one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates generally to apparatuses and methods forbrazing bearing components such as bearing rings that include bearingelements comprising superhard materials. “Superhard,” as used herein,refers to any material having a hardness that is at least equal to orexceeds a hardness of tungsten carbide (e.g., without limitation,polycrystalline diamond, boron nitride, silicon carbide, and mixtures ofthe foregoing). For example, in one embodiment, a polycrystallinediamond compact (PDC), or multiple PDCs, may be used to form a bearingsurface in the bearing elements and apparatuses of the presentlydisclosed invention. In another embodiment, polycrystalline diamond mayinclude nanodiamond (i.e., ultra-dispersed diamond), if desired. In yetanother example, the bearing surface may include a silicon carbide anddiamond composite material such as is disclosed in U.S. Pat. No.7,060,641, the disclosure of which is incorporated herein, in itsentirety, by this reference. A variety of other superhard materials maybe utilized in forming a superhard bearing in accordance with thepresently disclosed invention as will be appreciated by those ofordinary skill in the art.

Considering the example of a PDC, a PDC is conventionally fabricated byplacing a cemented carbide substrate into a container or cartridge witha layer of diamond crystals or grains positioned adjacent one surface ofa substrate. Cartridges may be loaded into an ultra-high pressure presswhere the substrates and adjacent diamond crystal layers are thensintered under ultra-high temperature and ultra-high pressure (“HPHT”)conditions. The ultra-high pressure and ultra-high temperatureconditions cause the diamond crystals or grains to bond to one anotherto form polycrystalline diamond with diamond-to-diamond bonds.Additionally, as known in the art, a catalyst may be employed forfacilitating formation of polycrystalline diamond. In one example, aso-called “solvent catalyst” may be employed for facilitating theformation of polycrystalline diamond. For example, cobalt, nickel, andiron are some non-limiting examples of solvent catalysts that may beused in forming polycrystalline diamond.

In one configuration, during sintering, the solvent catalyst may includethe substrate body (e.g., cobalt from a cobalt-cemented tungsten carbidesubstrate). In such a case, the solvent catalyst from the substratebecomes liquid and sweeps from the region adjacent to the diamond powderand into the diamond grains. In another embodiment, a solvent catalystmay be mixed with the diamond powder prior to sintering, either in lieuof, or in addition to, the existence of a solvent catalyst in thesubstrate. Thus, diamond grains become mutually bonded to form apolycrystalline diamond table upon the substrate. A conventional processfor forming polycrystalline diamond structures is disclosed in U.S. Pat.No. 3,745,623 to Wentorf, Jr. et al., the disclosure of which isincorporated, in its entirety, by this reference.

The solvent catalyst may remain in the polycrystalline diamond layerwithin the interstitial pores between the diamond grains or may be atleast partially removed to a desired depth, such as by leaching (e.g.,exposing at least a portion of the diamond table to an acid) or by anyother suitable method. Removal of the catalyst may enhance the thermalstability of the PDC material. Optionally, another material may replacethe solvent catalyst that has been at least partially removed from thepolycrystalline diamond.

In one embodiment, a bearing apparatus may include a bearing ring havingone or more polycrystalline diamond inserts or compacts defining one ormore surfaces configured to move relative to some other surface. Suchbearing apparatuses may encompass so-called thrust bearings, radialbearings, or other bearing apparatuses having bearing surfaces that movein relation to one another, without limitation. Examples of bearingassemblies and bearing elements are described in U.S. Pat. No. 8,210,747to Cooley et al. and U.S. patent application Ser. No. 13/294,048, filedon Nov. 10, 2011, the disclosures of which are incorporated by referenceherein in their entireties.

During the manufacture of a bearing assembly, bearing elements are oftendisposed in the pockets of a bearing ring. In many embodiments, it isconventional to affix the bearing elements within their respectivepockets through a brazing process. The brazing of the bearing elementsto the bearing ring takes place at an elevated temperature. For example,an inductive heating system may be used to heat the bearing ring in thebearing inserts to appropriate brazing temperature. One example of aninductive heating system is described in pending U.S. patent applicationSer. No. 12/425,304 filed on Apr. 16, 2009, entitled APPARATUSES ANDMETHODS FOR INDUCTION HEATING, the disclosure of which is incorporatedby reference herein in its entirety.

Referring to FIGS. 1-3, a fixture 100 is shown according to anembodiment of the present invention. The fixture 100 includes a body 102which, in this particular embodiment, exhibits a substantially annulargeometry. The fixture 100 includes a plurality of force applyingmechanisms, referred to herein as pusher mechanisms 104, that arecircumferentially spaced about the annular body 102. As will bediscussed in more detail below, each pusher mechanism 104 is configuredto selectively engage and push against, or provide a holding force for,a bearing element associated with a bearing ring. In the embodimentshown in FIGS. 1-3, the pusher mechanisms 104 each include a push rod106 that extends radially inwardly from a radially inner peripheralsurface 108 of the annular body 102.

FIG. 1 shows each push rod 106 placed in an extended state, or a statefor engagement with a corresponding bearing element. In the presentlydescribed embodiment, when the push rods 106 are in an extended state,the pushrods 106 extend radially inwardly to a first radius R1 thatcorresponds with a radius that is somewhat smaller than the bearingsurface defined by bearing elements of a bearing assembly. On the otherhand, FIG. 2 shows the pushrods 106 in a relatively retracted state.When in the retracted state, the pushrods 106 may still extend radiallyinwardly from the inner radial periphery 108 of the annular body 102,but they only extend up to a second radius R2, wherein R2 is greaterthan R1 when measured from the center point of the fixture 100 (see theintersection of axes 150A and 150B in FIGS. 1 and 2). In other words,when in an extended state, the end surfaces of the push rods 106 areable to be positioned further away from an associated surface (e.g., theinner radial periphery 108) of the annular body 102 than when in aretracted state.

In another embodiment, when the push rods 106 are in a retracted state,the radially innermost ends of the push rods may be retracted within theannular body 102 such that they do not protrude, radially inwardly,beyond the radially inner peripheral surface 108 of the body 102.

In addition to the push rod 106, the pusher mechanism 104 includes abiasing member 110 (e.g., a spring, such as a coil spring) and anactuator handle 112 coupled with the push rod 106. The push rod 106 andbiasing member 110 may be positioned in a generally radially extendingchannel 114 formed in the annular body 102 as may be seen in FIG. 3. Apin 116 may be positioned in the annular body 102 such that it traversesthe channel 114 and acts as a bracing or abutting member for the biasingmember 110, keeping the radially outermost portion of the biasing member110 at a desired location. The handle 112 extends from the push rod 106through an opening 118 formed in the annular body 102 that is incommunication with the channel 114. In one embodiment, the opening 118may be substantially L-shaped and configured so that the handle 112 maybe displaced along at least two different axes. For example, the handle112 (along with the push rod 106) may be displaced in a substantiallyradially direction along an axis that extends coincident with the lengthof a first leg 120 of the opening 118. It is noted that the first leg120 extends in substantially the same direction as the channel 114.Displacement in this direction coincides with the displacement of thepush rod 106 from an extended state to a retracted state (or vice versa)as discussed above.

The handle 112 may also be displaced in a second direction within asecond leg 122 of the opening 118 (e.g., a generally circumferentialdirection), the second direction being at an angle (e.g., generallyperpendicular) relative to the first direction. Displacement of thehandle 112 in the second direction may include rotation of the push rod106 about its longitudinal axis. When the handle 112 is displaced suchthat it is positioned within the second leg 122 of the opening 118, itholds the push rod 106 in a retracted position against the biasing forceof the biasing member 110 or other force applying member. This enables auser to maintain the push rod 106 in a retracted position whilepositioning a bearing assembly relative to the fixture 100. The user maythen place each push rod 106 into abutting engagement with an associatedbearing element by displacing the handle 112 from the second leg 122back into the first leg 120 so that the biasing member 110 displaces thepush rod 106 through the channel toward the extended position.

The fixture 100 may be made using various materials and manufacturingprocesses. For example, the annular body 102 may be formed from steel,stainless steel, or some other metal or metal alloy. Likewise, thepushrods 106 may be formed of steel, stainless steel or some other metalor alloy or a ceramic material. The biasing member 110 may be formed,for example, as a metal coil spring although other biasing members maybe utilized. The handle 112 may be formed of a metal or metal alloy and,in one particular embodiment, may comprise a threaded fastener, such asa cap bolt that is threadedly coupled to the push rod 106. In otherembodiments, the handle 112 may be welded, brazed or coupled with thepush rod 106 by other appropriate means. The various materials used tomanufacture the fixture 100 optionally exhibit high-strength propertiesand are able to withstand relatively high temperatures, as they may beutilized in a high temperature environment during the brazing of bearingelements to a bearing ring.

Additionally, it is contemplated that the various components of thefixture 100, including the body 102 and the pusher mechanisms, may takea different form than those specifically shown in the drawings or usedin the specific examples. For example, rather than using a spring or anelastic material for the biasing member, an actuating mechanism may beused. Some non-limiting examples of an actuating mechanism includehydraulic and pneumatic pistons, a solenoid, a screw jack or some otherlinear actuator. In such a case, the actuators may be self retractingor, optionally, a spring may be used to help retract the push rod to itsretracted state.

In one embodiment, the fixture 100 may be utilized in connection with aninduction heating process used to braze bearing elements to a bearingring such as, for example, one of the induction heating processes (alongwith the associated heating apparatuses) that are described in U.S.patent application Ser. No. 12/425,304, previously incorporated byreference. Of course, the fixture 100 may be used in other manufacturingprocesses and in association with other heating apparatuses as will beappreciated by those of ordinary skill in the art.

Referring now to FIG. 4, a bearing assembly 130 is positioned within thecenter opening of the fixture 100 such that the fixture 100substantially circumscribes the bearing assembly 130. FIGS. 5-7additionally show various views of an individual pusher mechanism 104with a bearing assembly 130 positioned adjacent thereto. The bearingassembly 130 includes a body or a bearing ring 132 having a pluralitybearing elements 134 disposed in cavities or openings formed in aradially outer surface of the bearing ring 132. In one embodiment, thebearing ring 132 may be formed, for example, of a stainless steelmaterial and the bearing elements may be formed as superabrasiveelements having, for example, a substrate with a superabrasive tablebonded to the substrate such as previously described.

As previously noted, during the manufacture of the bearing assembly 130,it may be desirable to braze the bearing elements 134 into the pockets136 formed in the bearing ring 132. In order to maintain the bearingelements 134 in a desired position and orientation within the pockets136 of the bearing ring 132, the pusher mechanisms 104 are actuated suchthat the pushrods 106 are in their deployed or extended positions andapply a force to an associated bearing element 134. It is noted that,when in a deployed condition or state, the push rods 106 need not befully extended from the body 102. Rather, for example, when contactingan associated bearing element 134, the push rod 106 may be at a radialposition that is somewhere between R1 and R2, or somewhere between R1and the inner peripheral radial surface 108 of the body 102. This mayenable a given fixture 100 to accommodate multiple sizes of bearingassemblies rather than being relegated to use with a single size ofbearing assembly.

In addition to applying a force to each bearing element 134, thecollective forces applied by the biasing members 110 (via the push rods106) hold the entire bearing assembly 130 in place relative to thefixture 100. The fixture 100 and bearing assembly 130 may then besubjected to elevated temperatures provided by a furnace or otherheating apparatus (such as an induction heating apparatus as describedin U.S. patent application Ser. No. 12/425,304). Thus, the bearingelements 134 are maintained in a desired position and orientation,relative to the bearing ring 132, until the brazing process is complete.Subsequent the brazing process, the user may retract the pushrods 106 bydisplacing the actuator handle 112 as discussed above to remove thebearing assembly 130 for any subsequent manufacturing or assemblyprocesses that may be needed or desired.

Referring now to FIGS. 8 and 9, another fixture 200 is shown withanother radial bearing assembly 230 (FIG. 9). The fixture 200 includes abody 202 which exhibits a substantially annular geometry. The fixture200 includes a plurality of force-applying or pusher mechanisms 204 thatare circumferentially spaced about the annular body 202. Each pushermechanism 204 is configured to selectively engage and push against, orprovide a holding force for, a bearing element 234 relative to a bearingring 232 of a bearing assembly 230 (FIG. 9). The pusher mechanisms 204each include a push rod 206 that extends radially outwardly from anouter radial periphery 208 of the annular body 202.

FIG. 8 shows each push rod 206 placed in an extended state, or a statefor engagement with a corresponding bearing element 234. In thepresently described embodiment, when the push rods 206 are in anextended state, the pushrods 206 extend radially outwardly to a firstradius r1 that is slightly larger than the radius of a collectivebearing surface defined by bearing elements 234 of a bearing assembly230. While not specifically shown in FIGS. 8 and 9, the pushrods 206 maybe placed in a relatively retracted state such as described above (e.g.,the embodiment described with respect to FIGS. 1-3). When in theretracted state, the pushrods 206 may still extend radially outwardlyfrom the outer radial periphery 208 of the annular body 202, but theyonly extend to a second radius r2, wherein r2 is smaller than r1 whenmeasured from the center point of the fixture 200 (see the intersectionof axes 250A and 250B in FIGS. 1 and 2). In other words, when in anextended state, the end surfaces of the push rods 206 are positionedfurther away from an associated surface (e.g., the outer radialperiphery 208) of the annular body 202 than when in a retracted state.In another embodiment, the radial outermost ends of the push rods 206may be fully retracted within the annular body 202 while in theretracted state.

In addition to the push rod 206, the pusher mechanism 204 includes abiasing member (not explicitly shown in FIGS. 8 and 9) and an actuatorhandle 212 coupled with the push rod 206, similar to the configurationdescribed herein above regarding pusher mechanisms 104. The push rod 206and biasing member 220 may be positioned in a generally radiallyextending channel formed in the annular body 202. A pin 216 may bepositioned in the annular body 202 such that it traverses the channeland acts as a bracing or abutting member for the biasing member, keepingthe radially innermost portion of the biasing member at a desiredlocation. The handle 212 extends from the push rod 206 through anopening 218 formed in the annular body 202 that is in communication withthe channel. In one embodiment, the opening 218 may be substantiallyL-shaped and configured so that the handle 212 may be displaced in atleast two different directions. For example, the handle 212 (along withthe push rod 206) may be displaced in a substantially radially directionalong the length of a first leg 220 of the opening. The first leg 220extends in substantially the same direction as the longitudinal axis ofthe channel and push rod 206. This displacement coincides with thedisplacement of the push rod 206 from an extended state to a retractedstate (and vice versa) as discussed above.

In one embodiment, the opening 218 may be substantially L-shaped andconfigured so that the handle 212 may be displaced along at least twodifferent axes. For example, the handle 212 (along with the push rod206) may be displaced in a substantially radially direction along anaxis that extends coincident with the length of a first leg 220 of theopening 218. It is noted that the first leg 220 extends in substantiallythe same direction as the channel 214. Displacement in this directioncoincides with the displacement of the push rod 106 from an extendedstate to a retracted state (or vice versa) as discussed above.

The handle 212 may also be displaced in a second direction within asecond leg 222 of the opening 218 (e.g., a generally circumferentialdirection), the second direction being at an angle (e.g., generallyperpendicular) relative to the first direction. Displacement of thehandle 212 in the second direction may include rotation of the push rod206 about its longitudinal axis. When the handle 212 is displaced suchthat it is positioned within the second leg 222 of the opening 218, itholds the push rod 206 in a retracted position against the biasing forceof the biasing member or other force applying member. This enables auser to maintain the push rod 206 in a retracted position whilepositioning a bearing assembly relative to the fixture 200. The user maythen place each push rod 206 into abutting engagement with an associatedbearing element by displacing the handle 212 from the second leg 222back into the first leg 220 so that the biasing member 220 displaces thepush rod 206 through the channel toward the extended position.

As with the fixture 100 describe above, the fixture 200 described withrespect to FIGS. 8 and 9 may be made using various materials andmanufacturing processes.

The bearing assembly 230 is positioned such that its central openingsubstantially circumscribes the fixture 200. The bearing assembly 230may be formed similar to the bearing assembly 130 described above,except that bearing elements 234 are positioned in pockets formed in anradially inner peripheral surface 236, rather than in a radially outerperipheral surface of the bearing ring 232.

As previously noted, during the manufacture of the bearing assembly 230,it may be desirable to braze the bearing elements 234 into the pocketsformed in the bearing ring 232. In order to maintain the bearingelements 234 in a desired position and orientation within the pockets ofthe bearing ring 232, the pusher mechanisms 204 are actuated such thatthe pushrods 206 are in their deployed or extended positions and apply aforce to an associated bearing element 234. In addition to applying aforce to each bearing element 234, the collective forces applied by thebiasing members 220 (via the push rods 206) hold the entire bearingassembly 230 in place relative to the fixture 200. The fixture 200 andbearing assembly 230 may then be subjected to elevated temperaturesprovided by a furnace or other heating apparatus (such as an inductionheating apparatus as described in U.S. patent application Ser. No.12/425,304). Thus, the bearing elements 234 are maintained in a desiredposition and orientation, relative to the bearing ring 232, until thebrazing process is complete. Subsequent the brazing process, the usermay retract the pushrods 206 by displacing the actuator handle 212 asdiscussed above to remove the bearing assembly 230 for any subsequentmanufacturing or assembly processes that may be needed or desired.

A variety of other expansion and contraction devices are alsocontemplated as being used in conjunction with the presently disclosedinvention and the invention is not considered to be limited to thespecific examples provided herein and other expanding or contractingmechanisms are contemplated as being used to apply a force to thebearing elements of a radial bearing apparatus. For example, a ringclamp may be used to bearing elements in place on an outer radialsurface of a bearing ring. Other examples might include one or morecollets or even a Hoberman-type structure (e.g., an expandable sphere orring) that includes multiple linkage members to accommodate expansionand contraction of the structure wherein the structure may be eitherlocked in place (e.g., in its expanded or its contracted state) orinclude a biasing member to bias it towards a desired state.

While the invention may be susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and have been described in detail herein.However, it should be understood that the invention is not intended tobe limited to the particular forms disclosed. Rather, the inventionincludes all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the followingappended claims.

What is claimed is:
 1. An assembly for use in manufacturing slidingbearings, the assembly comprising: a bearing ring; a plurality ofbearing elements positioned adjacent to the bearing ring; a fixturebody; a plurality of force-applying mechanisms assembled with the body,the plurality of force applying mechanisms each including a displaceableelement; wherein each of the plurality bearing elements is associatedwith a unique one of the plurality of force-applying mechanisms, andwherein each of the force-applying mechanisms individually applies aforce to its associated bearing element of the plurality of bearingelements.
 2. The assembly of claim 1, wherein the fixture body comprisesan annular body and wherein the plurality of force applying mechanismsare circumferentially spaced about the substantially annular body. 3.The assembly of claim 1, wherein each displaceable element is biased ina direction towards engagement with its associated individual bearingelement of the plurality of bearing elements.
 4. The assembly of claim1, wherein each displaceable element is configured to be selectivelydisplaced relative to the fixture body from an extended state to aretracted state.
 5. The assembly of claim 4, wherein each displaceableelement is selectively lockable in the retracted state.
 6. The assemblyof claim 4, wherein each displaceable element extends beyond a radiallyinner peripheral surface of the fixture body when in the extended state.7. The assembly of claim 4, wherein each displaceable element extendsbeyond a radially outer peripheral surface of the fixture body when inthe extended state.
 8. The assembly of claim 1, wherein a plurality ofchannels are defined in the fixture body and wherein each displaceableelement is disposed in an associated channel of the plurality ofchannels.
 9. An assembly for use in manufacturing sliding bearings, theassembly comprising: a bearing ring; a plurality of bearing elementspositioned adjacent to the bearing ring; a fixture body having aplurality of channels defined therein; a plurality of force-applyingmechanisms assembled with the body, the plurality of force applyingmechanisms each including a displaceable element disposed in anassociated one of the plurality of channels, wherein the displaceableelement comprises a push rod; wherein each of the force-applyingmechanisms applies a force to an individual bearing element of theplurality of bearing elements.
 10. The assembly of claim 9, wherein eachof the plurality of force-applying mechanisms includes a handle coupledwith the push rod.
 11. The assembly of claim 10, further comprising aplurality of openings in a surface of the fixture body, each of theplurality of openings being located adjacent an associated channel ofthe plurality of channels, wherein each handle extends through anassociated opening of the plurality of openings.
 12. The assembly ofclaim 11, wherein each opening is substantially L-shaped.
 13. Theassembly of claim 9, wherein each of the plurality of force-applyingmechanisms includes a biasing element associated with the push rod ofthe force-applying mechanism.
 14. The assembly of claim 1, wherein theeach displaceable element includes an arcuate surface configured forengagement with its associated individual bearing element of theplurality of bearing elements.
 15. The assembly of claim 1, wherein eachbearing element of the plurality of bearing elements comprises apolycrystalline diamond table bonded to a substrate.
 16. The assembly ofclaim 15, wherein the bearing ring and the plurality of bearing elementscollectively form a radial bearing ring.
 17. The assembly of claim 16,wherein each of the plurality of bearing elements comprise a convexbearing surface.
 18. The assembly of claim 16, wherein each of theplurality of bearing elements comprise a concave bearing surface. 19.The assembly of claim 1, wherein each displaceable element is configuredfor displacement longitudinally along an associated axis that extendsthrough the displaceable element and wherein each displaceable elementis also configured for rotational displacement about the associatedaxis.
 20. The assembly of claim 1, wherein each of the plurality ofbearing elements are positioned adjacent a radial outer surface of thebearing ring.
 21. The assembly of claim 1, wherein each of the pluralityof bearing elements are positioned adjacent a radial inner surface ofthe bearing ring.